The present invention relates to a method and device for allowing users to input directional instructions to an application of a portable autonomous device and, more particularly but not exclusively, to a method and device for allowing users to input directional instructions to an application of a portable autonomous device with limited computational abilities, using image processing.
The rapid miniaturization of complex electronic circuits and the emergence of high-resolution displays have vastly increased the number and variety of portable processor-based devices. Such devices include handheld computers, mobile telephones, pagers and other portable communication and computing solutions. Moreover, processing power, data storage capability, communication speed, and battery life of portable autonomous devices continue to develop at an accelerated pace.
Each one of the aforementioned portable autonomous devices usually integrates a man machine interface (MMI) that allows users to control its functioning. However, the MMI has to be adjusted to the small size of the portable autonomous device. The traditional MMI is a minimized keyboard or a keypad which allows users to input data having textual representation such as a telephone number, a contact name, word processor content, etc. The minimized keyboard or keypad may also be used as a pointing device.
Some portable autonomous devices integrate designated pointing devices in addition to their textual input devices. For example, recently developed mobile phones usually comprise a small joystick or a roller which enables users to operate the portable autonomous devices. Users may control the portable autonomous devices using the pointing devices by making selections on display screens which are connected to the devices. For example, using pointing devices, users can scroll the viewing areas by selecting the vertical or horizontal scroll bars on the display screens.
Another commonly used MMI is the touch screen. Personal digital assistants (PDAs), for example, usually integrate such touch screens and pen-like pointing device which are often stored next to or on the PDAs. In use, a pen-like pointing device is applied to a display area on a PDA to enable a user to make choices and interact with a PDA portable autonomous device. High resolution LCD touch screens may be used in mobile phones and portable devices. The disadvantages of using touch screens are their high price and limited transparency which reduces the picture quality, particularly of modern, high resolution LCD displays.
The rapid miniaturization and cost reduction of complex electronic components has recently led to the integration of image sensors into processor-based portable autonomous devices. PDAs, mobile phones, and laptops integrate cameras which are used to capture still and video images. This has enhanced the marketing potential of mobile phone handsets.
The integration of image sensors additionally allows users to interface with the portable processor-based devices. For example, it is known that outputs of image sensors may be used to calculate the displacement of objects. However, the known methods have several limitations as they rely on certain criteria to track the scene and they may not be reliable, scalable and robust. These limitations thus prevent the processor-based devices from performing certain functions using the displacement detection process. Moreover, the aforementioned methods do not facilitate an efficient utilization in portable autonomous devices with limited computational resources.
There is thus a widely recognized need for, and it would be highly advantageous to have, a portable processor-based device that allows users to input directional instructions, devoid of the above limitations